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Discrete time theories?

  1. Nov 12, 2013 #1
    Hello!

    I was told, that there are no mainstream physics theories, in which time is discrete.

    My question is this:

    At any present or any given future scenario, there will always exist the smallest amount of time, that a machine is able to measure. How come this variable, is not a main component of mainstream physics theories?
     
  2. jcsd
  3. Nov 12, 2013 #2

    ZapperZ

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    "Mainstream physics" are theories and idea that have been verified convincingly by experiment.

    You are also confusing a measured time using our metric versus the concept of time that is independent of our measuring devices. Just because we have a limit on how small of a time period that we can measure doesn't mean our description of time has that kind of discreteness. How come you didn't care that we also have the same limitation in how small of a distance that we can measure as well? That doesn't mean that our space dimension is also discrete. It could be, but it has nothing to do with what we are using to measure it!

    Zz.
     
  4. Nov 12, 2013 #3
    I do care that we also have the same limitation in how small of a distance we can measure !! If we know the speed of light, then one of them is enough to know the other, isn't that right? if that is correct, then isn't it the same variable? So, my question is, why & is that distance/time variable, a major part of mainstream physics theories and if it is, how exactly?

    If the answer is that it is not a part of mainstream theories, and "...it has nothing to do with what we are using to measure it!..." - then i don't understand that answer, please try to elaborate....


    Thanks.
     
  5. Nov 12, 2013 #4

    ZapperZ

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    We have theories that describe a certain part of our world. We use instruments to verify that theory. Our instruments have limitations, but the results that we get are consistent with the theory. Thus, we accept that the theory is valid, for now. The more validation we get, the better we know that theory and how to use it. Eventually, it becomes convincing enough that it moves from the research front area, into the mainstream physics that we teach students in schools.

    Our understanding of that phenomenon described by that theory is NOT governed by the instrument that we use. It is the theory that describes it. Now, apply it to space and time. What is the theory that is so well-known and so accepted that deals with space and time that it has become part of mainstream physics? Special and General Relativity! Now, does it contain discrete space and time in that theory?

    Zz.
     
  6. Nov 12, 2013 #5
    So, you are saying that adding to existing theories, a recognition about a role, that the smallest time/distance measurable period, might take in these theories, is not a theoretical move?
     
  7. Nov 12, 2013 #6

    ZapperZ

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    Try it! And then try to justify how you can still use calculus in such a situation. At what point does the differential equations that are the starting point for many of such description still makes sense?

    This is not how one formulates a theory.

    Zz.
     
  8. Nov 12, 2013 #7
    This is exactly what i am trying to understand, for a very long time - how an idea transforms into math and the problems surrounding this process. i even searched for courses on the subject, but couldn't find one.

    Can you give me a more detailed, and simple as possible, example, including the math, how an idea or a theory becomes a differential equation and how assuming that a measuring equipment has a minimum time/distance variable, disrupts this process of converting a theory into math?

    Please take into consideration that my math knowledge is a graduate's at most.

    Thanks a lot!
     
    Last edited: Nov 12, 2013
  9. Nov 13, 2013 #8

    Dale

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    Why should it be? Is there any accepted evidence to suggest that it is a fundamental part of the structure of the universe rather than a simple technological limitation?
     
  10. Nov 27, 2013 #9
    How do physicists tell the difference, between fundamental part of the structure of the universe and a simple technological limitation?
     
  11. Nov 27, 2013 #10

    AlephZero

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    You can find a way to overcome one of them. And that is one-sentence summary of what experimentalists have been doing, ever since the time of Galileo.

    But you can't change the other one!
     
  12. Nov 27, 2013 #11

    Chronos

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    I was under the impression that planck time was generally accepted as the smallest possible unit of time.
     
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